BackgroundWith the development of economy and technology, the Internet is becoming more and more popular. Internet addiction has gradually become a serious issue in public health worldwide. The number of Internet users in China has reached 731 million, with an estimated 24 million adolescents determined as having Internet addiction. In this meta-analysis, we attempted to estimate the prevalence of Internet addiction among College Students in the People’s Republic of China in order to improve the mental health level of college students and provide evidence for the prevention of Internet addiction.MethodsEligible articles about the prevalence of Internet addiction among college students in China published between 2006 and 2017 were retrieved from online Chinese periodicals, the full-text databases of Wan Fang, VIP, and the Chinese National Knowledge Infrastructure, as well as PubMed. Stata 11.0 was used to perform the analyses.ResultsA total of 26 papers were included in the analyses. The overall sample size was 38,245, with 4573 diagnosed with Internet addiction. The pooled detection rate of Internet addiction was 11% (95% confidence interval [CI] 9–13%) among college students in China. The detection rate was higher in male students (16%) than female students (8%). The Internet addiction detection rate was 11% (95% CI 8–14%) in southern areas, 11% (95% CI 7–14%) in northern areas, 13% (95% CI 8–18%) in eastern areas and 9% (95% CI 8–11%) in the mid-western areas. According to different scales, the Internet addiction detection rate was 11% (95% CI 8–15%) using the Young scale and 9% (95% CI 6–11%) using the Chen scale respectively. Cumulative meta analysis showed that the detection rate had a slight upward trend and gradually stabilized in the last 3 years.ConclusionThe pooled Internet addiction detection rate of Chinese college students in out study was 11%, which is higher than in some other countries and strongly demonstrates a worrisome situation. Effective measures should be taken to prevent further Internet addiction and improve the current situation.

Eco‐industrial parks (EIPs) is a complex system, composed of a variety of companies with embedded ties. Members in EIPs shape the “Eco‐Industrial Chain Network,” the industrial coupling symbiosis network (ICSN) system, in which businesses cooperate with each other and share the mutual benefits at the same time. In order to study the development levels of the ICSN system in EIPs, this paper uses the grey relational analysis (GRA) method to evaluate the eco‐efficiency of coupling and symbiosis network in EIPs in oil and gas resource‐based cities. The results show that the overall level of eco‐efficiency and the stability of ICSN could be reflected through the application of the economic, environmental, and the dematerialized cycle and network structure relational analysis. Furthermore, it confirms the feasibility and applicability of the evaluation model and the evaluation indicator system.

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Abstract. Land use changes alter the hydrological characteristics of the land surface, and have significant impacts on hydrological cycle and water balance, the analysis of complex effects on natural systems has become one of the main concerns. In this study, we generated the land use conversion matrixes using ArcGIS and selected several landscape indexes (contagion index, CONTAG, Shannon's diversity index, SHDI, etc.) to evaluate the impact of land use/cover changes on hydrological process in the upper reaches of Minjiang River. We also used a statistical regression model which was established based on hydrology and precipitation data during the period of 1959–2008 to simulate the impacts of different land use conditions on rainfall and runoff in different periods. Our results showed that the simulated annual mean flow from 1985 to 1995 and 1995 to 2008 are 9.19 and 1.04 m3 s−1 lower than the measured values, respectively, which implied that the ecological protection measures should be strengthened in the study area. Our study could provide a scientific basis for water resource management and proper land use planning of upper reaches of Minjiang River.

This paper attempts to focus on the application of the ecological carrying capacity theory and the three‐dimensional state‐space model to th eco‐efficiency evaluation of petrochemical enterprises. This research differs from the existing literature, which focuses on business’ eco‐efficiency from behavioral motivation and strategic perspective. This paper proposes a three‐dimensional state‐space model of ecological efficiency of petrochemical enterprises by adopting a combination of ecological carrying index and state space. This model in a three‐dimensional geometric space takes petrochemical enterprises as a pressurer for natural resources and natural environment. The three axes of space represent the economic status of petrochemical enterprises, the use of resources, and the impact of enterprises on the environment, respectively. It attempts to quantitatively describe economic activities of petrochemical enterprises and the interaction with resources and environment. It focuses on applying the model to calculate the ecological carrying capacity of petrochemical enterprises, verifying the feasibility and applicability of the model in calculating the ecological efficiency of enterprises, and providing theoretical tools for enterprises to make ecological efficiency judgments. The results show that this method can help to find out the problems with resources, economy, and environment during the development of petrochemical enterprises and provide the basis for managers to make strategic decisions of sustainable development.

This study uses the Charnes, Cooper and Rhodes (CCR) and Banker, Charnes and Cooper (BBC) models of Data Envelopment Analysis (DEA) to evaluate the relative eco-efficiency and operating efficiency of the ten petrochemical enterprises. A random sample of ten petrochemical enterprises were selected from the Northeastern area of China. The data collected from the ten petrochemical enterprises were run on the DEA models and the evaluated results were input for the difference analysis for the scale efficiency and technical efficiency. Then the estimates the petrochemical enterprise's operating efficiency and ecological efficiency along with the influencing factors were run by regression analysis in order to verify the evaluation model and the rationality of influencing factors. After the projection analysis of the DEA, the firms that did not reach the values of effectiveness were identified and provided the suggestions for the targeted improvement values of eco-efficiency. Thus, this application procedure can be viewed as an example of the application development of the new DEA model and provides the reference for related industry making sustainable development strategy.

Based on the pertinent literature at home and abroad, this paper made a comparative study on the concepts, models and characters of continuous and discontinuous innovation, and provided an important criterion to define continuous and discontinuous innovation-weather the technological trajectory and technological paradigm are same. According to the technological growth curve, the process of technological innovation is divided into the growth phase, plateau phase and transitional phase, then the paper proposed that the enterprises should adopt innovation combination, conduct continuous and discontinuous innovation management activities during technological growth and technology alternation, and the author built the manage model of the continuous and discontinuous innovation based on technological growth.